Supporting structure



Aug. 18, 1959 R. H. SAVAGE ETAL 2,900,014

SUPPORTING STRUCTURE Filed March 18, 1957 2 Sheets-Sheet 1 z I I IN VEN TORS r ROBERT M 341 465 Y REWARD 50am 72 ,5 i Y: I B i q I a 1 .3.

I Aug. 18, 1959 SAVAGE E AL 2,900,014

SUPPORTING STRUCTURE Filed March 18, 1957 2 Sheets-Sheet 2 INVENTORS E056???" H SAW/76f BY flaw/Q0 50/7 017 SUPPORTING STRUCTURE Robert H. Savage, Schwenksville, and Richard Schultz,

Barto, Pa., assignors, by mesne assignments, to Knoll Associates, Inc., New York, N.Y., a corporation of New York Application March 18, 1957, Serial No. 646,916

1 Claim. (Cl. 155196) This invention relates generally to supporting structures and particularly to means for mounting a panel, e.g. a

molded plastic seat shell, on a support, e.g. a metal base.

An increasingly common type of chair constructionincludes a seat shell molded of plastic material and a sup porting base, usually metal. The seat shell may also include an integral back and/ or arms.

.The most common form of connection between'the plastic seat shell and the supporting base, in chairs of this type, has involved the use of bolts or the like with heads projecting above or countersunk in the top of the seat, resulting in an unsightly and even uncomfortable arrangement.

Some attempts have heretofore been made to mount molded plastic seat shells upon bases using structures which do not penetrate the shell and which thereby leave the upper surface of the seat with a smooth, unbroken contour. However, such structures heretofore proposed have been unable to prevent localized stresses at the regions of connection. The presence of such localized stresses has resulted in a weakening of the connection after a relatively short period of use, with attendant loosening and even local failure of the chair structure.

An object of my invention is to provide an improved connecting means between a molded plastic seat shell and a base of the type in which the connecting means in no way penetrates or otherwise protrudes from the upper or edge surface of the seat.

Y Another object of my invention is to provide an improved connecting means of the type described, which is effective to distribute the stress occasioned by a load upon a seat or other panel. More particularly, this object is to spread the stress over a large region of the seat shell and conversely substantially to prevent localized stresses either at the point of connection of the shell or panel and the support, or elsewhere.

Another object of my invention is to provide an improved connecting means for a plastic seat shell and a supporting base, which connecting means is constructed to allow for manufacturing tolerances with respect to the spacing of the points of connection on the seat shell and on the base.

Another object of my invention is to provide a chair construction which is easily, quickly and economically manufactured and assembled.

Another object is to provide an improved supporting structure for a panel or the like.

, The foregoing and other objects of my invention are attained, in the structure described herein, by providing a chair comprising a molded seat shell, a base, and connecting means comprising a pair of metal stampings, preferably steel, each having a central channel portion and flanged marginal portions curved to fit the underside of the molded seat shell. These stampings extend transversely across the underside of the seat shell from side to side and are connected thereto by bonding the flanged marginal portions to the underside of the shell by any suitable bonding agent. The central channel portion of each stamping is provided adjacent each of its transice versely opposite ends with first and second apertures.

- The first aperture at each end is adapted to receive a single-turn threaded clip which may, for example, be of the type commercially known as a Tinnerman Speed- Nut. The second aperture at each end is adapted to receive a bolt or screw for cooperation with the clip. The shell is mounted upon a suitable base by extending a threaded bolt upwardly through a hole formed in a base member adjacent the shell and through the second of the two above-mentioned apertures in the central portion of the stamping. The bolt threadedly engages the threaded sides of an aperture in one arm of the clip,

whose arms are located on opposite sides of the second stamping aperture. The second stamping aperture 1s made larger than the bolt. Further, the clips are received with substantial clearance in the first stamping apertures,

so as to permit substantial tolerances in the alignment of the various parts during the manufacturing process.

Other objects and advantages of the invention will become apparent from a consideration of the following description and claim, taken together with the accompanying drawings, in which:

Fig. 1 represents a perspective view of a chair constructed according to my invention, taken from below and to thefront of the chair;

Fig. 2 is an elevational view of one of the stampings to which are attached threaded clips;

Fig. 3 is a sectional view partly on the lines 33 of Fig. 2, showing the stamping bonded to a seat shell;

Fig. 4 is a fragmentary transverse sectional view through a partially assembled chair, showing the seat shell and an attached metal stamping;

Fig. 5 is a fragmentary transverse sectional view similar to Fig. 4, but showing a completely assembled chair, including a seat shell, a base, and a connection between the shell and base constructed in accordance with the invention; v

Fig. 6 is a perspective view of a threaded clip; taken from above and to one side showing one arm thereof; and

Fig. 7 is a view similar to Fig. 6 except that the clip has been inverted to show the other arm thereof.

Figure 1 shows a chair generally indicated by the nu; meral 1 comprising a seat 2 mounted upon a base 3. Seat 2 is preferably made of molded plastic but may be constructed of any suitable resilient material whet'he-r molded, stamped, or otherwisefabricated. Other suitable materials include sheet metal and plywood. Base 3 is preferably constructed of rods of any light, strong metal and is provided, adjacent seat 2, with two parallel rods 4 which, in the structure illustrated, extend from front to rear of the base.

The supporting connection betweenthe rods '4 and. the seat 2 is constructed in accordance with the present invention. Each rod 4 has two apertures formed near the opposite ends thereof and adapted to receive b01313. Only one such aperture is shown in detail in the drawing, at 4a in Fig.5.

Two elongated stampings 5 are provided, each having a longitudinally extending, depressed central portion defining a channel and two integrally formed lateral flanges bonded to the underside of seat 2 by any suitable bonding agent, indicated at 9. Each stamping is curved longitudinally to fit the underside of seat 2. In the embodiment shown, the lateral flanges 8 are joined at their ends by integral end flanges 7, which are also bonded to the seat 2. Flats 10 are provided at each end of the depressed central portion of each stamping 5. The stampings 5 are positioned in the embodiment shown, to extend transversely across the seat from side to side across the greater part of the width thereof.

An opening 5a is located at the outer endsof each of the flats 10, and an opening b is located centrally of each flat 10. A U-shaped leaf spring clip 12 has one arm inserted through aperture 5a along the inside of the flat 10. The clip 12 yieldably and frictionally engages the flat: 10. The spring clip 12 is provided with aligned apertures edges deformed to provide a single-turn thread adapted to engage the thread on the bolt, as shown in Fig. 5. Openings 5b are substantially circular and adapted to freely receive the bolt 13. In the preferred embodiment to points of connection is possible, resulting in ease and of my invention openings 5a are nearer the ends of the stamping 5 than are the openings 5b. This relative positioning, however, is not entirely necessary. Other relative positions may be used.

Openings 5b are formed so as to have a diameter greater than the diameter of apertures 12a and 12b of the clip, and the spring clip is movable within opening 5a over a range substantially equal to the difference in diameter between the apertures of the clip and openings 5b of stamping 6.

As thus described, the chair embodying the novel features of this invention is assembled by:

(1) Transversely attaching two metal stampings 5 to chair shell 2 by bonding the flanges thereof to the underside of seat 2;

(2) Inserting in openings 5a spring clips 12;

(3) Aligning base rods 4 substantially perpendicular to stampings 5 so that base'apertures 4a of each base rod are substantially aligned with opening 5b formed at the ends of stampings 5; and r (4) Passing bolts 7 13 successively and respectively through base rod apertures 4a, clip apertures 12a, stamping openings 5b and clip apertures 12b, and securing the parts defining such apertures by the interaction of the threaded clip and the bolt.

The metal stampings 5 are formed of material, preferably steel, considerably stiffer than the seat shell 2. Consequently, the stampings 5 reinforce the shell and effectively limit the deformation of the bonded surface thereof under load. The deformation of the shell in that region is limited sufliciently so that the bond does not loosen due to flexing under load. The chair base is directly connected to opposite ends of this metal stamping and not directly to the seat. There is a substantial expanse of the stiff material of the stamping between each point of connection to the base and the flanges attached to the seat. All of that expanse of material is effective to absorb and distribute stresses. Furthermore, a substantial area of the seat is attached to the flanges and stresses applied to the seat are distributed over all of that area. it, will be seen that no part is subjected to substantial lo callzed stress in a chair constructed according to this invention. Stress occasioned by a downward force upon Applicants have thus disclosed a chair construction which permits the mounting of an elongated molded shell upon a metal base so that no penetration or outward marring of the smooth surface of the shell results. Further, localized stressed areas at the point of connection of a shell and base is substantially eliminated, and stress is distributed over a large area of the chair seat surface.

Further, adjustment of the various parts with respect economy of assembly.

Each stamping, in the preferred embodiment of my invention, is manufactured from metal, preferably steel about 7 to /s in thickness.

Further, this connecting means may be manufacture from sheet metal as a metal stamping and is therefore susceptible of inexpensive mass production.

/ While I have shown and described a preferred embodiment of my invention, other modifications thereof will readily occur to those skilled in the art, and I therefore intend to be limited only by the scope of the ap-. pended claim. Particularly, it is at once apparent that this invention may be used to connect any light, resilient 1 material to a base where distribution of stress and continuity of outer surface is desired as, for example, in assembly of prefabricated walls and ceilings, or in constructing molded tables, desks, sinktops, etc.

What is claimed is:

A chair structure comprising a one-piece, curved seat having a smooth concave upper surface adapted to be directly engaged by the body of a seated person and a smooth, convex under surface, a pair of curved elongated metal stamping connecting members extending transversely of the under surface of said seat near the front and rear portions thereof and having a length somewhat less than the width of said seat, each said member comprising two side flanges and two end flanges cooperating to form an integral, generally horizontally extending, peripheral flange contoured to conform to the under surface of the seat, a channel portion integral with and between said side flanges and extending downwardly therefrom, said channel portion including downwardly extending side and end walls adjoining the re-' spective side and end flanges, and a central web connecting the lower ends of the walls and curved concentrically with the flanges and the under surface of the seat, a pair of horizontal flat portions integral with the web at the opposite ends thereof, each'said flat por- "tion being provided with a first aperture near the cento the under surface of the seat, a base supporting said Thus, 7

seat and including horizontal support elements extending under said first apertures, and having holes therein aligned with said first apertures, four' screws each having its threaded end passing through an aligned aperture and hole, and four nuts within said connecting members, accessible through said second apertures and the upper surface of the chair seat is distributed through the entire length of stampings 5 and to all of the connections between the stampings and the base, and is not concentrated at the localized points of shel1base connection as is similar stress upon shell-base connections of chairs constructed under present manufacturing techniques.

It will be noted that should apertures 4a o-fthe base rods not be initially in exact alignment with openings 51) V References Cited in the fileof this patent V, UNITED STATES PATENTS Tinnerman June 22, 1937 2,103,874 Shwayder Dec. 28, 1937 2,565,613 Ludwig Au g.'28, 1951 2,572,591 Booth Oct. 23, 1951 2,703,136 Masse Mar. 1, 1955 Hojman Nov. 1, 1955 

